Summary The float-equipped deHavilland DHC-2Beaver aircraft, registration C-FEYQ, serial number465, operated by Blue Water Aviation Services, departed Bissett, Manitoba, at approximately 0910 central daylight time (CDT). The aircraft's load comprised the pilot, three passengers, passenger baggage, and two 16-foot canoes strapped to the float strut assemblies, one on each float. The purpose of the flight was to transport canoeists to Sasaginnigak Lake approximately 38miles north of Bissett. The trip was estimated to take 22to 24minutes. Approximately 18minutes into the flight, the engine low fuel pressure warning light illuminated, and the engine began to lose power. The pilot switched tanks from the centre fuel tank to the front tank and began to manually operate the fuel wobble pump. The engine sputtered a few times, but did not regain power. The aircraft was descending over land at this point and the pilot was forced to put the aircraft down through trees into a rocky outcrop area. The aircraft overturned during touchdown and the pilot and three passengers exited the aircraft uninjured. The aircraft was spotted several hours later by an overflying aircraft. There was no emergency locator transmitter (ELT) on board the aircraft. A helicopter was dispatched and the pilot and passengers were transported to a nearby hospital for observation. The accident occurred during the daylight hours at 0930 CDT. Ce rapport est galement disponible en franais. Other Factual Information The pilot held a valid Canadian commercial pilot licence, rated for land and sea operations. According to Transport Canada and company documentation, the pilot was qualified and fit to perform the flight. The weather observation for Bissett at 0900 central daylight time (CDT)1 was as follows: surface temperature 28C, temperature at 1000feet 30C, and winds less than 10knots out of the south. This was the pilot's third flight of the day. It was company policy to fly external loads early in the morning when the temperatures were cooler. The first flight was flown approximately four hours earlier with three passengers and one externally strapped canoe. The temperature at that time was approximately 18C, or 10degrees cooler than at the time of the occurrence trip. The second flight consisted of three legs. The first leg was flown with freight only, the second leg empty, and the third leg with four passengers and baggage. The pilot reported no performance problems with the aircraft on either of these two flights at cooler temperatures. Company operations personnel reported that an external load trip would not normally be scheduled to depart in high ambient temperature conditions. The temperature at the time of departure for the occurrence flight was unusually high. The occurrence flight would have been the pilot's last external load flight that day. Prior to the occurrence flight, the pilot put approximately 50litres (13.25USgallons) of fuel into the centre tank, which was nearly empty. The front fuel tank already contained approximately 113litres (30USgallons) from the previous flight. The pilot's normal practice was to burn fuel from the centre tank first, then switch to the front tank for landing. At a fuel burn rate of approximately 25USgallons per hour (gph), the pilot estimated that he had a duration of about 32minutes of flight time on the centre tank, or enough fuel to handle the outbound leg of the trip. After the occurrence, the average fuel burn rate for segments of the first two flights of the day was calculated from log book entries to be between 22and 28USgph, or close to the 25USgph stated in the aircraft flight manual. The flight up to the time of the engine power loss was flown entirely on the centre fuel tank. On this type of flight, the pilot would normally climb to a minimum cruising altitude of 2500feet above sea level (asl). Because of the high ambient air temperature and the increased drag caused by the canoes tied onto the aircraft's floats, the pilot levelled off at 1700feet asl, 700feet above ground level (agl), and set the engine power to a normal cruise power setting of 28inches of manifold pressure and 1800rpm. At this power setting, the engine temperatures were normal and the carburettor heat was in the yellow range with no reported loss of aircraft altitude. The lower cruising altitude was selected so as not to prolong the use of climb power and risk overheating the engine; it was at that altitude when the engine lost power. The design service ceiling of the float equipped DHC-2Mk1Beaver is 15750feet asl. Carrying external loads on an aircraft increases the aerodynamic drag in flight, adversely affecting aircraft performance. The company's operations manual, Section3.14.1, prohibits the carriage of passengers when external loads are being carried, unless authorized in the aircraft's Type Certificate or Supplemental Type Certificate (STC). The Type Certificate for the DHC-2Beaver contains direction and limitations governing the carriage of external loads, but it does not authorize the carriage of passengers when external loads are being carried. The company did not hold an STC for the DHC-2Beaver. No documentation was found indicating an exemption to3.14.1 of the company's operations manual had been approved or was in effect. There is no known STC that allows the external carriage of two canoes on the aircraft. Canadian Aviation Regulation (CAR)703.25 prohibits the carriage of external loads with passengers onboard, unless otherwise authorized in the aircraft's Type Certificate or STC. There is, however, an exemption to CAR703.25 published in the Commercial and Business Aviation Advisory Circular, No.0209 (CBAAC0209, formally CBAAC 0152R - SeeAppendixA). The exemption was issued by Transport Canada, after representation from industry, to allow operators to carry external loads and passengers simultaneously without having these authorities. The CBAAC0209 Advisory Circular is made up of two documents, the Advisory Circular and the exemption to CAR703.25 document. In the purpose statement of the Advisory Circular it states: This exemption will permit operators to carry passengers and an external load, without authorization in the Type Certificate or in a supplemental Type Certificate (STC), provided that certain conditions are met. In the Purpose and Application statement of the exemption to CAR703.25 document it states: The purpose of this exemption is to allow Canadian air operators to carry external loads on their float equipped aeroplanes without authorization in the aeroplane type certificate or in a supplemental type certificate. This exemption does not apply to operators that have been authorized in the aeroplane type certificate or supplemental type certificate to carry external loads. CBAAC 0209 requires that operators meet certain conditions if they wish to operate under this exemption, and requires that the company's operations manual be amended to indicate that the operator is conducting external load operations in accordance with the conditions of the exemption. A review of company and Transport Canada documentation indicated that none of the conditions of CBAAC0209 had been met. Interviews with several Transport Canada inspectors in the Prairie and Northern Region and the Ontario Region revealed varying and substantially different interpretations as to how the exemption (CBAAC0209) was applied. Specifically there was confusion as to when the aircraft Type Certificate governed the carriage of external loads and when the conditions of CBAAC0209 governed carriage of external loads. There was concern among the inspectors that CBAAC0209 contained no finite restrictions regarding weight, quantity, and dimensions, creating the potential for operators to carry large, non-aerodynamic external loads that could exceed the performance capabilities of their aircraft. They believed that the wording in CBAAC0209 was ambiguous in its application and that it would be unreasonable to expect operators to have a uniform understanding of the exemption and its application with the current wording. The investigation revealed that most of the company's senior operations personnel and the pilot in command had a limited knowledge and understanding of existing regulations governing the carriage of external loads. The carriage of external loads with passengers was common practice at the company and the pilot had done so in the past. One of the requirements of CBAAC0209 is that formal and documented training be conducted on the carriage of external loads. Some company training had been done, but it was neither formal nor documented. The training information available from the company's operations manual and training program was incomplete and not in accordance with the normal operating practices of the company or the requirements of the CARs. CBAAC 0209 does not permit operators to exceed the performance capabilities of their aircraft. It requires, when passengers plus external loads are carried, that the maximum take-off weight of the aircraft be reduced by twice the weight of the external load. On the occurrence aircraft, the pilot was aware that the external load and high outside temperatures would affect aircraft performance and he limited the load in an ad hoc manner. It was calculated that at the time of take-off, the aircraft was 350to 400pounds below its maximum take-off weight of 5090pounds. An examination of the wreckage was done approximately one week after the occurrence. As the first indication of an anomaly was the illumination of the fuel pressure warning light, the aircraft's fuel system was examined in detail. The fuel delivery system in the DHCBeaver is a suction feed system, with the engine driven fuel pump drawing fuel from the fuel tanks in the belly of the aircraft. The aircraft had been inverted since the day of the accident and most of the fuel that had been in the aircraft had either drained out or evaporated. The fuel that was recovered was free of water and contamination. The engine and airframe fuel system screens were removed and found to be clean and free of obstructions. The fuel tanks and fuel lines were found to be free from foreign obstructions and the fuel selector valve was found to operate normally. The fuel selector valve was found selected to the forward tank. Photo1.Inline fuel system check valves During the examination of the aircraft, two anomalies were noted in the fuel delivery system. The first anomaly involved one of the two inline fuel system check valves (seePhoto1). The check valves were stamped with the same body number (525GGD), but only one valve was stamped with the original component manufacturer's part number (P/N)3-744-75. The valve without the original component manufacturer's P/N stamp appeared to be of a different design. The internal flapper door on this valve had a stiffer return spring and the flapper door was found to contact the internal wall of the valve, preventing the door from opening fully. This check valve was installed in the main fuel line between the inlet and outlet lines connected to the wobble pump. Both valves were tested at the component manufacturer's facility in Irvine, California. The minimum flow requirement for the P/N3-744-75 valve is 110cubic centimeters per minute (cc/min) with a flow rate of 5inches of solvent. The flow rate for the approved P/N3-744-75 valve was measured at 132cc/min with the flow beginning at approximately 4inches of solvent. The flow rate for the non-approved valve was measured at 36cc/min with the flow eventually beginning at 5inches of solvent, after waiting a few seconds. The second anomaly was a significant kink in a section of the aluminum main engine fuel feed line (P/NC2P1017), mounted directly behind the engine oil cooler temperature regulating valve. The valve controls the flow of oil through the cooler. The kink was located on a bend in the line and had reduced the size of the line to approximately of its original diameter. The fuel line was located in a protected area of the fuselage and would not have been damaged from impact forces. As a result, the kink was believed to be damage caused during an unspecified maintenance action at some unknown time prior to the occurrence (seePhoto2). Photo2. Main engine fuel feed line The aircraft was not equipped with an optional electric fuel boost pump. The engine-driven fuel pump was removed and later flow-checked at an engine overhaul facility; the pump output pressure was below limits. It was not believed that the lower fuel pressure setting would have resulted in the engine power loss; however, the lower pump output pressure would have reduced the suction on the main engine feed line. The operator indicated that earlier in the season the aircraft's fuel pressure gauge was reading high, and that the wobble pump handle was moving up and down by itself. The operator reduced the fuel pump pressure, which seemed to cure the problem of the handle moving up and down. During the 2001/02 winter season, a major 800-hour inspection of the aircraft was carried out. The airframe time was 19705.8hours, and the inspection was signed as completed on 01May02. During the inspection, a fuel primer line, located in the area of the kinked main engine fuel feed line, was replaced and EDO4580 floats were reinstalled. The aircraft was inspected again on 24June02, four days prior to the occurrence, during a scheduled 100-hour maintenance inspection. During that inspection the fuel sumps were drained and the screens were cleaned. The survival kit was signed out as being inspected and the emergency locator transmitter (ELT) was re-certified. No record of the inline fuel check valves being replaced was found. The pilot could not locate the ELT in the aircraft after the accident. An examination of the wreckage revealed that the ELT mounting bracket straps were bent over and flattened against the ELT mounting tray. The ELT mounting tray and straps were in a protected part of the fuselage and would not have been damaged by the impact. The company could not explain why or when the ELT was removed from the aircraft, but indicated that the flattening of the mounting bracket straps could have occurred during the replacement of the elevator cables at the 800-hour inspection. CAR 605.39 (2) (b) allows an aircraft to be operated without a serviceable ELT for a period of up to 30days, providing certain conditions are met. One condition is that the operator displays on a readily visible placard within the aircraft cockpit, for the period of removal of the ELT from the aircraft, a notice stating that the ELT has been removed and setting out the date of removal. There was no entry in the log book to indicate that the ELT had been removed from the aircraft, nor was the aircraft placarded to indicate that the aircraft was operating without an ELT. The company's operations manual does not state what items are covered in the required training on the use of emergency equipment, in particular, knowledge about access to and use of the ELT in an emergency.